1. Field of Invention
Various embodiments of the present invention relate to an electronic device and, more particularly, to a semiconductor memory device.
2. Description of Related Art
A semiconductor memory device is a storage device that is realized using a semiconductor made from, for example, silicon (Si), germanium (Ge), gallium arsenide (GaAs) or indium phosphide (InP). Semiconductor memory devices can be classified into volatile memory devices and non-volatile memory devices.
Volatile memory devices are unable to retain the stored data when the power is off. Examples of the volatile memory devices may include Static RAM (SRAM), Dynamic RAM (DRAM) and Synchronous DRAM (SDRAM). Non-volatile memory devices can retain the stored data regardless of power on/off conditions. Examples of the non-volatile memory include Read Only Memory (ROM), Mask ROM (MROM), Programmable ROM (PROM), Erasable Programmable ROM (EPROM), Electrically Erasable and Programmable ROM (EEPROM), flash memory, Phase-change Random Access Memory (PRAM), Magnetic RAM (MRAM), Resistive RAM (RRAM) and Ferroelectric RAM (FRAM). Flash memories may be classified into NOR-type memories and NAND-type memories.